Method of and apparatus for removing burrs from metallic fasteners



1940- w. E. SWIFT ETAL 2,224,993

METHOD OF AND APPARATUS FOR REMOVING BURRS FROM METALLIC FASTENERS FiledMay 25, 1938 2 Sheets-Sheet 1 in mm .322.

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METHOD OF AND APPARATUS FOR REMOVING BURRS FROM METALLIC FASTENERS FiledMay 25, 1938 2 Sheets-Sheet 2 lllllllI-lllii IIIIIIIIII .zfcgrja 4e- 46l "@25- 11. f j

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Patented Dec. 17, 1940 PATENT OFFICE T Q METHOD or AND APPARATUS FortRE- MOVING BURKS FROM METALLIC FAS- TENEBS' Willard E. Swift and GeorgeA. Anderson, Worcester, Mass, assignors to United States Envelope Maine7 Claims. The present invention relates to metallic fasteners of thetype providing projecting tongues necessary to use the fingers and ithas been found that the existence of burrsor rough edgeson the tonguesis liable to cause finger injuries to persons handling large numbers ofenvelopes.

. The object of the present invention is to provide an improved methodof and apparatus for removing burrs or rough edges from the bendabletongues of metallic fasteners, so that these tongues can always be bentby the fingers without any possibility of injury. In carrying out theinvention, the bendable tongues of metallic fasteners are subjected to acompressing action which forms rounded corners where. there previouslyexisted burrs, or edge roughness, resulting from initial punching of thetongues from sheet material. The invention further contemplates lateraldeflection of the tongues, simultaneously with the burr removal, so thatthe tongues will be offset from the plane of theenvelope wall when:attached thereto, in order to facilitate initial bending of the tongue.The above and other advantageous features of the invention willhereinafter more fully appear from the following description consideredin connection with the accompanying drawings in which:

.. Fig. 1 is a plan view of a metallic fastener.

Fig. 2 is an enlarged sectional view along the line 22.of Fig. 1. a

Fig. 3 is a plan view of a die for receiving the tongues of the fastenershown in Fig. 1.

- Fig. 4 is a sectional view of the die of Fig. 3

with a cooperating punch, shown in elevation.

Figs. 5 and 6 are sectional views, on an enlarged scale, illustratingthe removal of burrs from the fastener tongues.

' Fig. 7 is an edge view of a completed fastener.

Fig.8 shows the fastener of Fig. '7 applied to an F s. 11 and 12.are'diagrammatic, views il Company, Springfield, Mass, :a corporationof 2 Application May 25, 1938, Serial No. 209,900 I 29-13 1' i. Ilustrating the removal of burrs from fastener tongues, as initiallyformedin strip material. 3

Fig. 13 is'afr'agmentary view, showing the burr-- removing mechanism ofFig. 10 on an enlarged scale.

' Like reference characters refer to like parts in the differentfigures.

Referring first to Fig. l, the invention is shown,- for purposes ofillustration, as applied to a fastener of the type disclosed in SwiftPatent No. 1,593,048, issued July 20, 1926, although, as willhereinafter appear, the invention can be practiced in connection withother forms of fasteners of thisisame general construction. Such afastener comprises a base l provided at its four corners with bent-overattaching prongs 2 for piercing the back wall of an envelope preparatoryto being clinched on the under side of the wall, in a manner well knownin the art. A pair of flat bendable tongues 3 extend laterally from thecentral portion of the base I, and with the fastener attached to anenvelope, upward bendingof the tongues 3 brings them into registry witha'holeprovided inthe seal flap of an envelope,- as indicated in dottedlines in Fig. 8. After such registration, the tongues 3 are bent backinto horizontal position to retain the flap closed.

Heretofore fasteners of the type shown inFig. l-have-usuallybeen'blanked out'from strip materialby means of a suitable punchand-die, with the prongs 2 lying fiat, as indicated in dotted lines. Theedges of the punched tongues '3 on the punch side of a blank will oftenbe so rough as to provide appreciable burrs, indicated at 3a inthe'enlarged sectional showing of Fig. 2, due to'the molecular flowageof metal around the edges of the blanking punch. The presence of suchroughness or burrs 3a. therefore results in cutting or scratching thefingers of a person; such asa mailing clerk, who may be called upon tobendthe tongues of a large number of envelopes, and there will next bedescribed a method and apparatus for eliminating such burrs fromthebendable tongues of metallic fasteners.

As best shown in Figs. 3 and 4, a die 4 is provided which is formed withdepressions 5'each having an outline substantially conforming to thetongues 3 of a fastener. The outer portions 5a of the depressions 5 liein a common'plane, offset from a common plane in which lie the innerportions 5b. The portions 5a and 5b are joined by an inclined portion50, and the central portion of the die is cut away at 6. The die 4 isrigidly mounted on a block 1, and-a plunger 8 slidable in the block Iprovides a set of alining pins 9 freely movable through openings Iextending through the die 4. The pins 9 and the openings I are soarranged that when a fastener of the type shown in Fig. 1 is placed overthe die 4, movement of the pins 9 into the -corners between the prongs 2and tongues 3 will serve to accurately register the tongues 3 with thedie depressions 5.

With the tongues 3 of a fastener thus registered with the diedepressions 5, it is evident from Fig. 5 that the rough edges or burrs3a of a tongue will face towards the bottom of a depression.Furthermore, the sides 5d of a depression 5 are slightly inclinedoutwardly and join the bottom of the depression with a curvature that issubstantially the same as the curvature of the smooth edges of a tongue3 opposite the burrs 3a. It is also to be noted that the average widthof a die depression 5 between the inclined sides 5d is substantially thesame as the width of a fastener tongue 3, so that a. tongue may readilyenter a die depression 5 where it is widest.

After the tongues 3 of a fastener have been positioned in registry withthe die depressions 5, a punch II is brought to bear on the fastener andthen moved to force the tongues 3 into the depressions 5. As thisoccurs, the burred edges of each tongue engage the inclined sides 5d ofa die depression before the tongue is entirely forced into thedepression, as indicated in dotted lines in Fig. 5. Consequently, as thepunch II moves, to force the tongues completely into the diedepressions,v there occurs a compression along the rough or burred edgesof both tongues. The effect of this compression is shown in Fig. 6, fromwhich it is evident that the burrs 3a have been entirely eliminated, andthat the compressed tongues 3 possess smooth rounded edges on bothsides.

The forcing of the fastener tongues 3 into the portions 5a and 5b of thedepressions 5, as described above, also has the effect of laterallydeforming the tongues, so that their extremities are in a common planeoffset from the plane of the central base portion I of the fastenerwhich does not undergo any compression by the punch H, due to the factthat the die is cut away-at 6. Consequently, the tongues 3 are entirelyfree to conform to the shape of the depressions 5, which results inremoval of the burrs or edge roughness and in offsetting the extremitiesof the tongues with respect to the remainder of the fastener.

A fastener is shown in Fig. 7 as it appears after being operated upon bythe cooperating punch I I and die 4, from which it is evident that theattaching prongs 2 project oppositely with respect to the offset ends ofthe tongues 3. Consequently, when the fastener is attached to the rearwall I2 of an envelope by clinching over the prongs 2, the extremitiesof the tongues 3 are appreciably displaced from the outer surface of theenvelope wall !2. Therefore, the prongs 3 may be readily seized by thefingers in order to bend them upwardly into the dotted line positionpreparatory to inserting the bent prongs into an opening provided by theseal flap of the envelope. Obviously such bending of the tongues 3 canbe accomplished, as desired, without possibility of injuring thefingers, due to the previous removal of all rough edges from the tonguesas a result of the compressing operation.

Referring-now to Fig. 9, there is indicated diagrammatically thefunctioning of a punch and die for compressing the tongues of metallicfasteners while the fasteners are still in flat blank form. In thisarrangement, a metal strip I3 is operated upon by a punch I4 whichserves to punch fiat blanks from the strip I3, with the burred edges ofthe tongues 3 uppermost. The flat blanks are then moved by a. suitableconveyor I5 into registry with the depressions 5 of a die 4 mountedabove the conveyor. The tongues 3 are then operated upon by the punch IIand die 4 which serve to compress the tongues and remove all burrs orroughness from the edges thereof. The blanks are then delivered to asuitable container I5 in which they are stacked in flat form. The blanksin the container I6 can be handled as a unit and utilized by anysuitable fastener attaching mechanism.

In Fig. 10 there. is shown an arrangement wherein a magazine I? isprovided containing a stack of flat fastener blanks just as they arepunched from strip material. These fastener blanks are adapted to beremoved one by one from the magazine I l by a device which also. servesto bend the prongs 2 in advance of delivery of the blanks to a chute I8. A suitable mechanism for removing the blanks from the magazine I1 andbending the prongs thereon is fully shown and described in Patent No.1,993,059, dated March 5, 1935, and for the purposes of the presentapplication only certain essential parts of this mechanism will be nextdescribed, in order to set forth its cooperation with apparatus forremoving burrs from the fastener tongues 3 in advance of the applicationof a fastener to an envelope.

The fastener blank magazine. I1 comprises. spaced uprights I9, eachproviding a longitudinal slot for receiving the oppositely extendingtongues 3 of the fastener blanks. The distance between the uprights I9is such as to freely receive the flat prongs projecting from the body Iof the blanks and so maintain the blanks in alinement with the magazinewhile permitting vertical movement of the blanks in the stack as theyare removed one by one. The base of the magazine I! provides ahorizontally movable anvil which is adapted toreceive a reciprocatorymotion from a lever 26 operated by a cam 22 mounted on a shaft 23 towhich is imparted an intermittent rotative movement.

The anvil 20 provides a seat substantially equal to the thickness of ablank in the magazine I'I, so that when the anvil is moved forwardly bythe cam 22, a blank will be separated from the stack and carried intothe prong bending position. With a blank positioned on the anvil. 20,the oppositely projecting pairs of flat prongs 2 extend beneath a pairof benders 2 slidably mounted to move parallel to the sides of the anvil20. The benders 24- are adapted to be reciprocated in unison. bymechanism fully described in the aforesaid Patent No. 1,993,059, thismechanism being actuated from a cam 25 mounted on. the shaft 23. Therelation between the cams 22 and 25 is such that, following movement ofthe anvil 2G to remove a fastener blank from the magazine H, the benders24 will move downwardly in unison to engage the flat prongs on oppositesides of the tongues 3 and bend them downwardly, without disturbing thetongues 3.

Upon withdrawal of the anvil 20 following bending of the prongs 2, thefastener is stripped from the anvil and falls into the delivery chute I8through which it passes to mechanism for removing the burrs from theprongs 3. In this mechanism "a die 4, ofthe character previouslydescribed; is mounted vertically on a block I and. a plunger 8 slidablein the block 1 provides horizontally disposed alining pins 9 freelymovable through openings in the die 4, as best shown in Fig. 13. Theplunger 8 is connected by 'a' yieldable link 25 to a fork 21 embracing ashaft 28 driven from the shaft 23. A roll 29 mounted on thefork 2! bearson a cam 30 turnable with the shaft 28, so as to impart a reciprocatorymovement'to the link 26 and slide 8. A second yieldable link 35 isconnected to the fork 21 and to a crank arm 32 connected to the punch llthrough an eccentric 33.

The-cam 30 is so timed with respect to the anvil and bender-camsi22 and25 .that when a fastener is released into the chute I8 it comes to restin a vertical position when the pins 9 engage the body on opposite sidesof a tongue 3. Continued rotation of the shaft 28 then causes the punchl I to force the tongues 3 into the die depressions 5 with the removalof all burrs, as previously described. This movement of the punch IIwith respect to the die 4 is permitted by the pins 9, due to theyielding link 28 between the slide 8 and the yoke 27. As the shaft 28completes its rotation, the fingers 9 will be withdrawn, therebypermitting a fastener with smooth tongues 3 to fall into a lower chuteportion l8a leading to a fastener attaching station. The pins 9 thenreturn tothe position of Fig. 10 in readiness to intercept the nextfastener that is stripped from the anvil 20 following the performance ofa prong bending operation thereon.

A plunger 34 is provided at the fastener attaching station, the plunger34 being carried by a reciprocatory head 35 driven from the shaft 23through a crank 35. The crank 36 isso timed that the plunger 34 is inits raised position when the pins 9 deliver a fastener to the chuteportion 18a, the curvature of which causes the fastener to be positionedin a horizontal plane below the raised plunger 34. Upon arrival of afastener at the attaching station, it is yieldingly supported above ahorn 3'! by devices which are fully described in the aforesaid PatentNo. 1,993,059. The function of the horn 31 is to receive and support therear wall l2 of an envelope when the latter is delivered by a suitabletransfer mechanism from a stack 38 and cooperating feeding device 39.The envelope transfer mechanism is so timed that the rear wall of anenvelope is positioned on the horn 31 coincidentally with the arrival ofa fastener, after which the plunger 34 descends to force the downwardlyextending prongs 2 of the fastener through the envelope wall and clinchthem over against the wall of the envelope.

Referring now to Figs. 11 and 12, there is shown an arrangement forremoving burrs from tongues that are formed in a metal strip in advanceof the punching of a complete fastener blank from the strip. In thismechanism, a strip 40 is operated upon at intervals by a punch 4| anddie 42 which cause separated tongues 43 to be cut out of the strip. Thestrip 40 is then advanced for operation upon by a pair of rolls 44 and45. The upper roll 44 provides die depressions 46, while the lower rollprovides punch projections 41 raised above the periphery of the roll.

The rolls 44 and 45 are substantially cylindrical in form, except forthe depressions 46 and projections 41, and the circumference of eachroll is slightly greater than the distance between the extremities of anopposed pair of punched-out tongues 43; Since the die depressions 46 aresimilarin form to the die depressions 5, previously described withreference to Fig. 3, passage of the strip 4l]'betvveen the rolls 44 and45, with proper registration of the tongues 43 with the die depressions43, will result in compressing the tongues 43 so as to remove all burrs,or other roughness, therefrom. After passage of the strip lilibetweenthe rolls 44 and 45 the compressed tongues: 43-eXtend above the plane ofthe strip, asindicated in Fig. 11, and the strip may now be acted uponby the punch 48 which serves to sever a portion of the strip between thetongues 43,

so as to constitute' the'body portion of a fastener blank. The cut madein the strip 40 by the punch 48 is indicated at 49 in Fig. 12.

From the foregoing it is apparent that by the present invention there isprovided an improved method of and apparatus for removing any burrs orrough places from the bendable tongues of metallic envelope fasteners,so that these tongues can be freely manipulated by the fingers withoutpossibility of injury. In carrying out the invention, the operation uponthe tongues to remove the burrs canv be performed either upon acompleted fastener, upon fastener blanks, before or after the formationof the attaching prongs, or upon tongues formed in strip material inadvance of the punching out of complete blanks.

We claim,

1. Apparatus for removing edge roughness from the tongues of metallicfasteners, comprising a die having depressions with rounded contours,means for positioning a fastener with the rough edges of its tonguesfacing toward said die depressions and a punch for forcing the tonguesof a fastener into said depressions to form rounded edges on saidtongues.

2. In apparatus of the class described, the combination with a supply ofmetallic fasteners providing bendable tongues, and means for removingfasteners from said supply for delivery to a fastener attaching station,of means interposed between said fastener supply and said attachingstation for removing edge roughness from the tongues of said fasteners.

3. In apparatus of the class described, the combination with means forconveying envelopes one by one to a fastener attaching station, a supplyof metallic fasteners providing bendable tongues, and means for removingfasteners from said supply for delivery to said fastener attachingstation, of means interposed between said fastener supply and saidattaching station, and operating in timed relation with said envelopedelivery and fastener feeding means, for removing edge roughness fromthe tongues of said fasteners.

4. Apparatus for removing edge burrs from the tongues of punchedmetallic fasteners, comprising a die providing a depression having anoutline substantially conforming to a fastener tongue with thelongitudinal sides of the depression inclined outwardly, means forpositioning a fastener with the edge burrs of a tongue facing toward thebottom of said die depression, and a punch for forcing said fastenertongue into said depression to convert said burrs into rounded edges.

5. Apparatus for removing edge burrs from the tongues of punchedmetallic fasteners,- comprising a die providing a depression having anoutline substantially conforming to a fastener tongue with thelongitudinal sides of the depression inclined outwardly, means forpositioning a fastener with the edge burrs of a tongue facing to- Wardthe bottom of said die depression, said fastener tongue being of suchwidth as to be supported by said inclined sides above the bottom of thedie depression, and a punch for forcing said tongue completely into saiddie depression to convert said burrs into rounded edges.

6'. Apparatus for operating. on metallic fasteners of the type havingtongues and attaching means, comprising a die having depressions withrounded contours, means for positioning a metallic fastener with therough edges of its tongues facing towards said die depressions, and apunch for forcing the tongues of a fastener into said depressions toform rounded edges on said tongues, and to offset the end portions ofthe tongues from the plane of that portion of the fastener carrying theattaching means.

'7. Apparatus for operating on punched metallic, fasteners of the typehaving tongues and body attaching means between said tongues, comprisinga die providing a depression having an outline substantially conformingto a fastener tongue, with the longitudinal sides of the depressioninclined outwardly, and with the bottom of the depression lying indifferent planes, means for positioning a fastener with the edge burrsof a tongue facing toward the bottom of said die depression, and. apunchfor forcing said fastener tongue into said depression to convertsaid burrs into rounded edges, and to offset the end portion of thetongue from the plane of that portion of the fastener carrying theattaching means.

WILLARD E. SWIFI. GEORGE A. ANDERSON.

